// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import {ITypeAndVersion} from "../interfaces/ITypeAndVersion.sol";

abstract contract OCR2Abstract is ITypeAndVersion {
  uint256 internal constant MAX_NUM_ORACLES = 31;
  uint256 private constant PREFIX_MASK = type(uint256).max << (256 - 16); // 0xFFFF00..00
  uint256 private constant PREFIX = 0x0001 << (256 - 16); // 0x000100..00

  /// @notice triggers a new run of the offchain reporting protocol
  /// @param previousConfigBlockNumber block in which the previous config was set, to simplify historic analysis
  /// @param configDigest configDigest of this configuration
  /// @param configCount ordinal number of this config setting among all config settings over the life of this contract
  /// @param signers ith element is address ith oracle uses to sign a report
  /// @param transmitters ith element is address ith oracle uses to transmit a report via the transmit method
  /// @param f maximum number of faulty/dishonest oracles the protocol can tolerate while still working correctly
  /// @param onchainConfig serialized configuration used by the contract (and possibly oracles)
  /// @param offchainConfigVersion version of the serialization format used for "offchainConfig" parameter
  /// @param offchainConfig serialized configuration used by the oracles exclusively and only passed through the contract
  event ConfigSet(
    uint32 previousConfigBlockNumber,
    bytes32 configDigest,
    uint64 configCount,
    address[] signers,
    address[] transmitters,
    uint8 f,
    bytes onchainConfig,
    uint64 offchainConfigVersion,
    bytes offchainConfig
  );

  /// @notice sets offchain reporting protocol configuration incl. participating oracles
  /// @param signers addresses with which oracles sign the reports
  /// @param transmitters addresses oracles use to transmit the reports
  /// @param f number of faulty oracles the system can tolerate
  /// @param onchainConfig serialized configuration used by the contract (and possibly oracles)
  /// @param offchainConfigVersion version number for offchainEncoding schema
  /// @param offchainConfig serialized configuration used by the oracles exclusively and only passed through the contract
  function setConfig(
    address[] memory signers,
    address[] memory transmitters,
    uint8 f,
    bytes memory onchainConfig,
    uint64 offchainConfigVersion,
    bytes memory offchainConfig
  ) external virtual;

  /// @notice information about current offchain reporting protocol configuration
  /// @return configCount ordinal number of current config, out of all configs applied to this contract so far
  /// @return blockNumber block at which this config was set
  /// @return configDigest domain-separation tag for current config (see _configDigestFromConfigData)
  function latestConfigDetails()
    external
    view
    virtual
    returns (uint32 configCount, uint32 blockNumber, bytes32 configDigest);

  function _configDigestFromConfigData(
    uint256 chainId,
    address contractAddress,
    uint64 configCount,
    address[] memory signers,
    address[] memory transmitters,
    uint8 f,
    bytes memory onchainConfig,
    uint64 offchainConfigVersion,
    bytes memory offchainConfig
  ) internal pure returns (bytes32) {
    uint256 h = uint256(
      keccak256(
        abi.encode(
          chainId,
          contractAddress,
          configCount,
          signers,
          transmitters,
          f,
          onchainConfig,
          offchainConfigVersion,
          offchainConfig
        )
      )
    );
    return bytes32((PREFIX & PREFIX_MASK) | (h & ~PREFIX_MASK));
  }

  /// @notice optionally emitted to indicate the latest configDigest and epoch for
  /// which a report was successfully transmitted. Alternatively, the contract may
  /// use latestConfigDigestAndEpoch with scanLogs set to false.
  event Transmitted(bytes32 configDigest, uint32 epoch);

  /// @notice optionally returns the latest configDigest and epoch for which a
  /// report was successfully transmitted. Alternatively, the contract may return
  /// scanLogs set to true and use Transmitted events to provide this information
  /// to offchain watchers.
  /// @return scanLogs indicates whether to rely on the configDigest and epoch
  /// returned or whether to scan logs for the Transmitted event instead.
  /// @return configDigest
  /// @return epoch
  function latestConfigDigestAndEpoch()
    external
    view
    virtual
    returns (bool scanLogs, bytes32 configDigest, uint32 epoch);

  /// @notice transmit is called to post a new report to the contract
  /// @param reportContext [0]: ConfigDigest, [1]: 27 byte padding, 4-byte epoch and 1-byte round, [2]: ExtraHash
  /// @param report serialized report, which the signatures are signing.
  /// @param rs ith element is the R components of the ith signature on report. Must have at most MAX_NUM_ORACLES entries
  /// @param ss ith element is the S components of the ith signature on report. Must have at most MAX_NUM_ORACLES entries
  /// @param rawVs ith element is the the V component of the ith signature
  function transmit(
    // NOTE: If these parameters are changed, expectedMsgDataLength and/or
    // TRANSMIT_MSGDATA_CONSTANT_LENGTH_COMPONENT need to be changed accordingly
    bytes32[3] calldata reportContext,
    bytes calldata report,
    bytes32[] calldata rs,
    bytes32[] calldata ss,
    bytes32 rawVs // signatures
  ) external virtual;
}